Tomatoes are a favorite crop for many home gardeners, and even beginner gardeners can have success when growing their very first tomato plant. But if you really want to improve your tomato-growing skills and see bigger and better yields than ever before, I’m going to let you in on a few “trade secrets”. As a former organic market farmer, I’ve had lots of experience growing thousands of tomato plants over the years. As a result, I’ve put together a list of 12 tomato growing secrets to use in your home garden for healthier plants, bigger yields, and less work.
12 Tomato Growing Secrets
While some of these tomato growing secrets involve tomato planting tips and soil health, others are focused on how to properly care for tomato plants throughout the growing season. However, each of these tomato growing secrets is aimed at helping you minimize work while maximizing the harvest.
Tomato growing secret #1: Phosphorous is a big deal
Tomatoes love sun. At least 6 hours of full sun per day is ideal. But did you know they also need nutrient-dense soil with a particular focus on ample phosphorous? Of the big three plant macro-nutrients [nitrogen (N), phosphorous (P), and potassium (K)], phosphorous is the one that encourages the development of sturdy roots and plenty of flowers and fruits. Gardeners who over-feed their tomatoes with high-nitrogen fertilizers have big, leafy green tomato plants with few flowers and fruits.
Instead of using a high-nitrogen fertilizer, one of the easiest tomato growing secrets to follow is to choose an organic granular tomato fertilizer that’s slightly higher in phosphorous (the middle number on the bag). It provides a form of slow-release phosphorous that’s available to the plant throughout the growing season without also piling on an excess of nitrogen. Here’s more on how to read a fertilizer label.
Tomato tip #2: Soil pH matters
While most gardeners haven’t a clue what the pH of their soil is, this important number influences tomato production big time. The ideal soil pH for maximum tomato plant nutrient absorption is between 6.2 and 6.5. That means that when your soil pH is within that range, the plant’s roots can absorb the greatest diversity of nutrients. Invest in a high-quality do-at-home soil test kit and follow the instructions in the results for adjusting your existing pH to reach this optimum target. Here’s more on how to adjust soil pH.
Tomato growing secret #3: Warm soil equals a faster start
Tomatoes are a warm-weather crop. They don’t tolerate frosts, and they don’t like cold “feet”. Warming up the soil prior to planting improves early root growth and gets the plants off to a better start. It’s a tomato growing secret many gardeners don’t always consider. To warm the soil prior to planting your tomato crop, cover the soil in black plastic sheeting or black biodegradable sheet mulch for two weeks. The plastic absorbs the sun’s energy and warms the soil. Leave it in place for a few weeks and then take it off prior to planting, or cut holes in the sheeting and plant the tomatoes right through it. If you choose the latter option, the plastic also helps control weeds through the growing season.
Some gardeners don’t like using anything plastic around food plants, so if that’s the case for you, use the biodegradable sheet mulch or skip using this tomato growing secret. However, the use of plastic mulches is allowed under the US National Organic Standards Program, as long as the plastic is removed at the end of the growing season and not turned into the soil.
Tomato planting tip #4: Protect plants for an earlier harvest
If you’d like a tomato growing secret you can use to get a jump-start on tomato season, or if you’re aiming to harvest ripe tomatoes a few weeks earlier than your neighbors, consider using some type of weather protection so you can plant earlier. Remember, tomatoes like hot weather, but surrounding newly planted transplants with a some type of insulation allows you to plant tomatoes a few week’s earlier. Look for protective cone-shaped, dual-walled plastic insulators that you fill with water. The water holds the day’s heat, releasing it at night to keep the plants warm. Use one around each plant for the first few weeks after planting. When the weather heats up, drain and remove it.
Another tomato growing secret is to use clay drainage pipes cut in half lengthwise. Prop a half a drain pipe against each side of your tomato stake (see photo) and over the plant. The clay absorbs the sun’s heat all day and then releases it through the night. The clay drainage pipes won’t protect tomato plants from heavy frosts, but they will shield them from light frosts and give them a jump start in cool spring weather.
Tomato plant secret #5: Go deep or horizontal
Unlike other garden vegetables, tomato plants are able to form roots all along their stems (called adventitious roots). Smart gardeners take advantage of this by planting tomato transplants either very deeply or horizontally, burying as much of the stem as possible. Deep and horizontal tomato planting results in an extensive root system that’s better able to handle drought and access soil nutrients.
No matter how tall your tomato transplant is, at planting time, use your thumb and forefinger to pinch off all of the leaves except the top 4. Then, either dig hole deep enough to bury the plant all the way up to the base of the lowest remaining leaf, or dig a horizontal trench and lay the plant’s stem down on its side in the trench. Then bury the plant, bending the tip up carefully so it’s sticking out of the soil.
Success secret #6: Loose roots are better than tight
When you take a tomato transplant out of its container or cell pack, take a good look at the roots. They’re probably circling around the inside of the container to form a thick, tangled mass. Prior to planting, use your fingers to tear apart the root ball and loosen it. Don’t worry; you don’t have to be gentle about this process. Dig in and pull the roots apart. When you plant, the root mass should not be in the shape of the container. Loosening or tearing the roots prior to planting encourages the roots to spread out into the existing soil, rather than continuing to circle around in the shape of the pot. Spread the loosened roots out in the hole before covering them up with soil.
Tomato growing tip #7: Always interplant
Looking for a tomato growing secret to help reduce pests? Interplanting is the answer! Never plant your tomatoes alone; always plant them with a few friends. Herbs in the carrot family, such as dill, fennel, and cilantro, make great companion plants for tomatoes. They provide nectar for the parasitic wasps that help gardeners control tomato hornworms. Sweet alyssum is another great flower to interplant with tomatoes. It provides nectar for several species of syrphid and tachinid flies who prey on pests like aphids, whiteflies, leaf-footed bugs, and tomato fruit worms. For more on companion planting, check out my book Plant Partners: Science-based Companion Planting Strategies for the Vegetable Garden.
Tomato growing secret #8: Welcome bumblebees
Along with the previous tomato growing tip, this one involves encouraging good bugs. Tomato flowers are self-fertile (meaning they’re capable of pollinating themselves), but they need vibration to knock the pollen off the anthers to fertilize the flower and produce a tomato. Though strong winds are capable of vibrating tomato flowers, bumblebees do a far better job of it. Bumblebees perform what is called “buzz pollination”. They vibrate their flight muscles (at the same wavelength of a middle C) as they nectar on the tomato flowers, knocking the pollen loose as they go. Encourage bumblebees in your tomato garden by planting lots of their favorite flowers. The list includes baptisia, blueberries, sunflowers, coneflowers, phlox, and lupines. For more tips on encouraging bumblebees, visit this article.
Grow tip #9: Mulch immediately after planting
Savvy gardeners take advantage of this tomato growing secret without fail. Mulch tomato transplants immediately after planting, using weedless straw, shredded leaves, or untreated grass clippings. Not only does mulch reduce weeding and watering needs throughout the season, but perhaps most importantly, it suppresses common soil-borne tomato diseases, such as blight and leaf spot. Since the spores of these pathogens are found in the soil, the mulch keeps rainwater from splashing the spores up onto the plant foliage. The layer of mulch should be 2 to 3 inches thick, and it should be applied even before you water your newly planted tomato plants in.
Tomato success secret #10: Get rid of the lowest leaves
Another key practice for tomato disease suppression is to remove the bottom leaves of every tomato plant. Since the lowest leaves are closest to the soil, removing them means a reduced chance of fungal spore splash-up. I typically remove the leaves on the lowest 8 to 10 inches of plant stem, but some gardeners remove far more than that.
To remove the lowest leaves, use a pair of scissors or pruners to clip them off where they meet the main stem. If you already have signs of disease on your tomato plant, disinfect the scissors with a spray of Lysol or Clorox before moving on to the next plant so you don’t spread the disease from one plant to another. You can also use your finger and thumb to pinch off the leaves, but you should wash your hands before moving from a diseased plant to one that’s free of disease. Read this article for more on preventing and treating tomato diseases.
Growing tip #11: No “splash and dash” allowed
Tomato plants need plenty of water throughout the growing season. If you don’t provide consistent moisture, your tomatoes could develop a physiological disorder known as blossom-end rot. This is when the bottom of a tomato turns into a black, sunken canker. Blossom-end rot is a symptom of a lack of calcium in the developing fruit, but it’s not likely to be caused by a lack of calcium in your soil. Most soils have ample calcium. The primary way calcium moves into a plant is with water, so when the soil is not kept consistently moist, that calcium can’t be absorbed by the tomato plant’s roots. The result is a deficiency of calcium in the plant (but not in the soil). Adding calcium to the soil will not help. Proper watering is the answer.
To water tomato plants, set the hose nozzle at the base of the plant and let the water really soak in for a long time. Then go back and do it again. Don’t do what I call “splash and dash”, where you only wet the top inch of soil and then move on to the next plant. After effectively watering a tomato plant, you should be able to dig down with a trowel and find wet soil down to a depth of 10 to 12 inches. Deeper, once-a-week waterings are way better than a daily “splash and dash”.
Tomato growing secret #12: Prune. Or don’t.
Plenty of gardeners get hung up on whether or not to prune their tomato plants. The truth is that it doesn’t really matter whether or not you decide to prune your plants. As long as the plants have ample support from a tomato cage, trellis, or staking system, and you space the plants properly (more on how far apart to plant tomatoes here), you can choose to prune or you can choose not to prune. If you like a neat and tidy plant, prune out the suckers. For those who don’t mind a bushy, rambling plant, let the suckers grow out into full stems. Gardeners like me who fall somewhere in between, do some pruning but we’re not religious about it. When it comes to tomato pruning, I say to each his own.
With these 12 tomato growing secrets, you’re sure to have your best tomato harvest ever! We’d love to hear any additional tips you have in the comment section below.
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